Guys, I dunno about Last, but I think this is going too far in the wrong direction.
As for your pictures, you could use one of those programs to encode a copyright string into those pictures so you could tell for sure if it is yours. You (in addition) should put some sort of copyright warning on the site along with a small not-easily-removable string on the pictures themselves.
You can press charges if anybody else uses the pictures at that point and win with almost NO trouble, so long as the encoded copyright was in place.